Cementitious product and process of obtaining same



Patented June 10, 1930 UNITED STATES PATENT OFFICE ROBERT A. MARE, OF NORFOLK, VIRGINIA, ASSIGNOR T0 RAMAR SYNDICATE INCOR- PORATED, OF NORFOLK, VIRGINIA, A CORPORATION OF VIRGINIA CEMENTITIOUS PRODUCT AND PROCESS OF OBTAINING SAME N'o Drawing. Application filed January 12, 1924, Serial No. 685,895. Renewed July 31, 1926.

banana stalks,-and to some extent the invention embraces somewhat similar products made from 'Inarsh grasses, sedges and similar growths. a

In my U; S. Patent No. 1,166,848 have described the manufacture of pulp and paper, by a process involving the digestion of wood a and various other materials, with zinc sulfate solution, which may also contain other chemicals.

In my Patent No. 1,362,? 23 I have described the production of textile fibers by a similar digestive treatment. In a copending application, Serial No. 407,759 filed September 2, 1920, I have described the use of solutions of sulfate of iron, sulfate of copper, and various other sulfates, as digestive fluids, in which to treat wood or other materials for the production of paper and pulp and fibrous materials. In my copending, application 595,- 215 filed October 17, 1922, I have described the digesting of cane, either alone or mixed with various other woods, in digestive fluids containing zinc sulfate, potassium sulfate, or

sodium sulfate, or mixtures of these sulfates, with or without others. In my application 616,609 filed February 2, 1923, I have described the use of aluminum sulfate or magnesium sulfate, sodium sulfate, potassium sulfate, or mixtures of the same, for digesting Wood or cane material or mixtures of such materials. In my copending application 616,610 I have described the use of solution of kainit (a complex material saline deposit containing potassium sulfate, magnesium sulfate and magnesium chloride) as a component of the digestive fluid.

In all of the above cases, the sulfates themselves form the active chemical constituents of the digestive fluid, and it is not necessary to use sodium sulfide, caustic soda or the like, forthe digestion of such materials as above stated. In all of the above cases the time for cooking can be an hour or a few hours, and it is not necessary to employ a long period such as 8 or 10 hours up to 30 or 40 hours at high pressure, as insome of the prior processes proposed for the production of paper pulp, according to the prior art. The strength of the digestion solution as employed in my above mentioned cases, varies more or less, but in all cases is preferably substantially less than 5% and in many cases even as low as 1 or 2% solution has been found to give very satisfactory results. The digestion can be carried out in the ordinary digestors, made say of cast iron, as commonly used in the art.

In all of the above cases, the materials treated may be any of the ordinary woods, or cane, bamboo or various other vegetable materials, or mixtures of such materials, and the named materials all contain a substantial amount of intercellular cementing material, by which the fibers or fiber bundles are bound together in the original vegetable growth. After the digestion has been completed, the material can be run between rolls, or run through a pulper with water, or otherwise crushed and thereby reduced to a pulp, containing-about 100% of the content of the material used, excepting water solubles. The pulp can be used like pulp produced by other inlgthods, for the production of paper or the I will state that a particular digestive solution which has been found to give very satisfactory results, is one made by mixing two parts of zinc sulfate, one part of potassium sulfate, and two parts of sodium sulfate, and dissolving each in water and making the di gesting solution, in the proportion of say, 1.5 to 3 oimces of total salts per gallon, and another very satisfactory solution is one pro duced by mixing two parts of magnesium sulfate, two parts of sodium sulfate and one part of potassium sulfate, dissolving this mixture in water, in the proportion of about 1.5 to 4 ounces per gallon. These two solutions have been found to give very satisfactory results with all kinds of woody materials,

straw, marsh growth, cane, bamboo, banana 1 stalks and similar materials. While under some conditions, any of these sulfates can be used alone, it is found that when the fibrous or woody material under treatment contains a largepercentage of silica in any form (e. g. bamboo, canes, etc.) it is advisable to use potassium sulfate as one of theingredients of the digestive solution, in order to prevent the formation of gelatinous silicacompounds.

As in my cases asabove referred to, the digestive solution can be used over a considerable number of times and it is not necessary to evaporate the liquid to dryness and to calcine the materials each time, as has been the usual practice with the chemicals used in. some of the other processes heretofore proposed.

In carrying out the digestive process, apparently a small part of the carbohydrate constituents of the cementitious matter of the wood are converted into something resembling sugars, and these sugars are somewhat caramelized, during the cooking process, which gives a more or less brownish color to the pulp, and also gives a characteristic caramel-like odor to the digestive fluid after the same has been used one or more times.

After the digestive operation, the wood or other material can be pulped in any suitable manner, with water, in order to mechanically shatter the intercellular cementitious binder to some extent, although the same does not become soluble in my process, as in the processes heretofore generally used for pulp manufacture. After the'pulping operation above referred to, the material can be washed or can be run directly into a beating engine, and can be beaten therein, in accordance with the usual practice for a desired length of time, to convert the same into a pulp. It is preferable in most cases to operate the beater with the roll raised a considerable distance above the bed, particularly at the commencement of the beating operation. The roll can be gradually brought down during the beating operation, towards the bedplate, and if desired, thebeating operation can be continued for say, one to two hours, during which time the roll will be brought down to say 1 to 2 turns above the bed, in order to give a brush beating effect without I cutting or shortening the individual fibers.

The cementitious materials including the air duct and xylose systems, as is shown by microscopic investigation, and by actual prac tice, are largely reduced to extreme fineness, but to not become soluble. For this reason, by my processes, the pulp or paper stock runs freely on the Fourdrinier wire cloth, without clogging the latter and all resinous matters seem to be agglutinated to the fiber Without clogging the wire mesh.

During or after the beating operation (or after the pulping operation whether or not the pulp is to be beaten) a considerable proportion of the cementitious matter in the pulp can be removed, which operation can be conducted in an ordinary pulp washer, or the' beater may carry a co-ordinated washer for removing any desired part of the cementitious matter, during the beating operation, thus leaving when desired, clean, clear, individual fibers, free from the finely divided intercellular cementitious material.

Some kinds of pulps, that is to say the pulps from some of the above mentioned woody materials, are found to be improved somewhat for some purposes, by removing a portion of the cementitious matter in the mode above described, and the amount to be removed will depend upon the particular kind of pulp under operation, and the particular properties of the desired final pulp product. The fraction of the cementitious matter removed may be 5% to 12% based on the total quantity of the wood or other material. This removal can be made by means-of a screen forming a part of the pulp washer, or other separating device, In some cases the pulp as coming from the pulper, without going to a beater, can be washed to separate therefrom any desired portion of the intercellular cementitious material, and the washed pulp can be turned into wet or dry laps which reduce in a short time equally as well, to liquid pulp. Hence cheap semi-portable plants can operate where the said material is found and the plants moved to new sources of supply; the wet or dry pulp being shipped to permanent paper products mills.

There is in all cases produced a slurry containing cementitious matter of wood, in a considerable amount of aqueous liquid, such as water, and the slurry can be allowed to settle whereby the cementious matter drops out of the liquid vehicle, the latter can be decanted off, or the liquid can be drained ofi', say by the use of fine sieves, or equivalent arrangement. If desired, a filter press, or centrifugal separator, can be used, through which the entire amount of liquid from the pulp washing operations can be passed and the filter cake will consist of the cementitious matter of plant growth usually with a small proportion of the finer fibers.

The cementitious matter can be run into molds, when carrying any desired percentage of water, say as a mass of the consistency of mortar or putty which does not stick to the fingers. This can be pressed into the desired shape, and the molded articles can be dried in the molding press or after being taken out of the press. If desired, fillers can be incorporated with the cementitious matter, before or at the time of molding. Water-proofing agents can be added to the paste of the cementitious matter, before molding or the molded articles can be treated with a waterproofing agent. Suitable waterproofing agents are rosin size, rubber latex,

oil emulsions, asphalt emulsions or mixtures of these, and suitable precipitants can be incorporated therewith, either before molding or after molding or after molding and drying. The molded articles can also be subjected to a vulcanizing treatment, whether or not waterproofing agents (such as latex, rosin etc.) have been used. I find that addition of a small proportion of latex to the rosin size before adding the latter, aids in the agglutination of the intercellular cementitious material (e. g. one part latex to 2-3 parts rosin size) followed by a precipitant, say alum.

The molded articles (when no fillers or other admixtures are used) are light in weight and normally of a brownish color (in the airdry state) about the color of hemlock-tanned leather, but can be made of any desired color,

by the use of dyes, etc. They are also (even if no water-proofing agent is used) quite water-resistant, after air-drying, so that they can be soaked in water, for days and months at a time,'without becoming wet through. In fact a small piece (after drying in the air) immersed in water for about 24 hours was found, on examination, to be covered with a thin film of water, but the water had not penetrated the surface at all, so far as could be observed, the examination being made after breaking the piece.

/Vhen it is desired to further waterproof the articles, the pasty mass of the cementitious binder can be mixed with, say, 2 to 10% of rubber latex, before the molding operation.

. The molded articles, with or without waterproofing agents, when molded under pressure are strong, light and rigid, and rather tough, and take a good polish.

In certain of the appended claims, I employ the term wood and I intend thereby to designateproducts which are distinctively lignilied, such as hard woods, soft woods, cane,

bamboo, and banana stalks, as distinguished from such materials as grasses, sedges and the i like, which are of herbaceous nature.

I claim: l. A process which comprises digestivel cooking cellulosic material in a solution containing a sulfate, such solution bemg of aconcentration substantially below 5%, thereafter pulping the cellulosic material and separating a substantial part at least of the disintegrated cementitious connective matter from the pulp, and thereafter isolating such separated cementitious connective matter, and molding the same.

2. Disintegrated cementitious matter of vegetable growth, separate from the fibrous matter of such vegetable growth, and in an undissolved water-insoluble condition.

3. A process which comprises digesting wood in a solution containing a sulfate, such solution being of substantially less than 5% strength, and the digesting operation continued until the cementitious matter in the wood -the cementitious matter in an undissolved condition into a bulk of aqueous liquid, and recovering apart at least of the said cementitious matter from said liquid.

4. Disintegrated cementitious matter of vegetable growth, separate from the fibrous matter of such vegetable growth, and in an undissolved water-insoluble condition, such material being molded into form, and substantially waterproof.

5. A material including the disintegrated but undissolved cementitious matter of wood, substantially free from the cellulosic fibers.

6. A product including the disintegrated but undissolved cementitious matter of vegetable growth, which material is capable of being molded, either alone or in combination with other materials but free from large amounts of the long cellulose fibres of the original vegetable growth.

7. The herein described disintegrated but undissolved cementitious matter of wood, or mixtures containing the same, which material is capable of being formed and worked and water-proofed, and which material itself upon drying is capable of hardening to a solid state, such product being substantially free from cellulose fibers.

In testimony whereof I aflix my signature.

ROBERT A. MARR. 

